Oh how hard can it be

Funny, I'm falling into my own how-hard-can-it-be convex hull trap I described just three posts ago! It turns out my idea for a support mapping-based convex hull generator isn't that great after all. It works perfectly in 2D, but in 3D it turns out the surface can get concave during the process, which of course will mess up the whole thing, so just forget everything I ever said about convex hull now would you (except perhaps the part about it always being harder than you think)? Thanks. Back to the drawing board. There must be some way to compute convex hulls using only the support direction..